The analysis centered on Belle Haven, a historically under-resourced neighborhood in Menlo Park. The map below shows the three census block groups that make up the neighborhood and which will be used for the analysis.
This analysis uses Data from OCOF on flood risk to Belle Haven, given nine different potential scenarios of sea level rise and storm frequency.
Below is a map of of the maximum flood risk for Belle Haven. The maximum risk assumes a sea level rise of 50 centimeters and a storm strength that only occurs every 100 years.
Next, the report will use building footprint data from OpenStreetMap to determine damage and construct an estimate of where population and vehicles are located.
Below is a map of the buildings that would be impacted by the max flooding event in Belle Haven.
To compile an estimate of vehicles per building, several data sources were used.
Census data was used to get population data at the block level. Vehicle counts were retrieved from census data about vehicle availability per household. The total count of 2020 vehicles for the whole CBG were than matched to each building, assuming population was distributed evenly across buildings in a block, and vehicles were distributed evenly across the population.
EMFAC data was used to get a count for vehicles in the county, to be used for the rate of change of vehciles over decades
Disclaimer: The census data retrieved for population was missing two blocks in the Northwestern area of Belle Haven. Although this area would likely be affected by flood risk, the data may show under-representation due to this lack of data. Those blocks were removed from the vehicle data, but they are technically part of Belle Haven and will not be represented.
The dollar amount used to estimate damage in money to each car was calculated using Kelly Blue Book’s average price for a used car in 2022, which is $28,000. The price for a used car was chosen since the majority of car sales are for used cars.
Below is a map of the “average annualized loss” (AAL) for each building in vehicle damages for the year 2020 and 2050
The final map shows that Belle Haven will not have to worry much about flooding costs in the near future with AALs at zero dollars in 2020. In 2050, the likelihood of higher sea level rise casues a higher AAL for the neighborhood, but still relatively few buildings will have to worry about vehicle damage.
There is reason to expect that the derived AAL are still underestimates, because they do not account for increasing storm frequency and severity due to climate change.